Concerted efforts are on worldwide to minimize the greenhouse gas emission related to construction industry by developing environment-friendly concrete alternative to conventional concrete. The paper presents the development of Fly Ash (FA)/Ground Granulated Blast Furnace Slag (GGBFS)-based ambient cured fiber reinforced geopolymer concrete and its workability and strength characteristics with variation of binder proportion (FA and GGBFS) and superplasticizers. In the present study, Polycarboxylic (MasterPolyheed 8145 and MasterPolyheed 8146) and naphthalene (MasterRheobuild 918)-based superplasticizers were used to improve workability. Fluid-to-binder ratio was fixed as 0.6 and the ratio of sodium silicate-to-sodium hydroxide is taken as 2. The steel fiber was added to the mix in volume fraction of 1% by the volume of binder. The prepared geopolymer concrete is checked for the workability and specimens of size 150 mm × 150 mm × 150 mm were prepared. The impact of fineness of binder material is also studied. From test results, it is observed that polycarboxylic-based superplasticizer gave better workability and strength than naphthalene-based superplasticizer. Workability and the strength characteristics improved with the use of finer binder material. Further, FA:GGBFS ratio of 70:30 developed higher desired strength.

Description

Concrete is one of the most widely used construction materials, second only to water. The Portland cement is conventionally used as the primary binder to produce concrete. As estimated, the production of cement increased from 1.5 billion tons to 2.5 billion tons in 2010 (Vijaya, 2014). A ton of Portland cement production involves emission of about one ton of CO2. As CO2 is the major component of greenhouse gas, which contributes about 65% of global warming (Vijaya (2014), it is necessary to find the alternative to the Portland cement and to produce environment-friendly concrete.

Geopolymer is an inorganic polymer. It was developed by Davidovits during the late 1970s. He proposed that an alkaline liquid can be used to react with the Silicon (Si) and Aluminum (Al) in the source material of the geological origin or with byproduct materials such as Fly Ash (FA), Metakoline, Ground Granulated Blast Furnace Slag (GGBFS) and rice husk ash to produce binders due to chemical reaction that takes place in the polymerization process. Such binders are termed as ‘geopolymers’ (Vijaya, 2014), since normally the source materials are of “geo” logical origin and reaction is inorganic “polymerization”.